If you asked some of your single friends what they're looking for in a potential mate, you'd probably elicit a bunch of bashful smiles and receive scores of different answers. You might hear, for example, "tall," "wealthy," "nice," "good-looking," "intelligent," "a similar personality," "compatible likes," "ambitious," or even the occasional (and shameless) "dynamite-in-the-sack," but there's one item that's almost sure to appear near the top of everyone's wish list: "a good sense of humor." This is universal. In almost every culture, people want that special someone to make them laugh.

According to Rutgers evolutionary biologist Robert Lynch, when such a characteristic is so highly sought after, "That tends to be a hallmark of an evolutionary trait."

Lynch theorized that humor may be pivotal in some way to human reproductive success and mate selection. To delve deeper, he conducted a number of studies. In one, individual subjects were placed in a room where they watched clips of HBO comedian Bill Burr, whose politically-incorrect brand of comedy is quite divisive: people often love it or hate it. While in the room, the individuals' reactions to Burr's jokes were filmed and recorded. After viewing the clips, subjects took an implicit preference test, which requires takers to rapidly categorize two target concepts with an attribute in order to determine inherent biases or attitudes.

Lynch found that "participants laughed more in response to jokes that matched their implicit preferences." For example, people who associated men and women with stereotypical gender roles laughed much more at Burr's jokes about women.

Genuine laughter arises subconsciously, so it's notoriously hard to fake. This fact, combined with Lynch's findings, suggests that sense of humor is an excellent indicator of a person's true personality. Thus, it would make sense for relationship-seekers to require a compatible sense of humor.

"I can lie about what I like, but when I laugh, I identify my real preferences," Lynch told PBS' Nova. "That would account for why [sense of humor] is so important in mate selection."

Laughter, itself appears to be all about sociality, and more specifically, relationships, says University of Maryland neuroscientist and laughologist Robert Provine. (Note: "Laughologist" is my made-up title for him.) For example, women tend to laugh more at men they deem attractive.

"A woman doesn't think I want this man to like me so I'm going to laugh a lot," Provine told Science Focus. "It just happens."

As evidence for laughter's social function, it has been gauged to be thirty times less frequent in solitary situations compared to social ones. This, you probably already realize. It's why comedies are far more enjoyable to watch with a group than by yourself. Laughter appears to be an innate signal of group cohesiveness, a way to identify with other individuals.

In summary, sense of humor may very well be a true indicator of character, with laughter as its mechanism. So whether you chuckle or chortle, guffaw or giggle, you'll probably find yourself drawn to individuals who regularly tickle your funny bone.